Perhaps you should try some spelling variations:
"charities, voluntary exertions" » "charities, voluntary exertion", "charities, voluntary deductions", "charities, voluntary donations"
"charities, voluntary service" » "charities, voluntary services", "charities, voluntary exercise", "charities, military service"

You may be able to get more results by adjusting your search query.

• The words AND, OR and NOT may confuse the search; try adding quotes: "((\"charities, voluntary service\") OR (\"charities, voluntary exertions\"))".
• Removing quotes may allow a broader search: (( charities, voluntary service ) OR ( charities, voluntary exertions )).
• Adding a wildcard symbol may retrieve word variants: (("charities, voluntary service") OR ("charities, voluntary exertions"))*.